EP0990128B1 - Pressure sensor with compensation for null shift non-linearity at very low temperatures - Google Patents
Pressure sensor with compensation for null shift non-linearity at very low temperatures Download PDFInfo
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- EP0990128B1 EP0990128B1 EP99910415A EP99910415A EP0990128B1 EP 0990128 B1 EP0990128 B1 EP 0990128B1 EP 99910415 A EP99910415 A EP 99910415A EP 99910415 A EP99910415 A EP 99910415A EP 0990128 B1 EP0990128 B1 EP 0990128B1
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- Prior art keywords
- bridge
- compensation
- temperature
- linearity
- resistance
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
- G01L1/2268—Arrangements for correcting or for compensating unwanted effects
- G01L1/2281—Arrangements for correcting or for compensating unwanted effects for temperature variations
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/02—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
- G01L9/04—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning of resistance-strain gauges
- G01L9/045—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning of resistance-strain gauges with electric temperature compensating means
Definitions
- the present invention relates to a pressure sensor of the type with strain gauges mounted respectively in the branches of a Wheatstone bridge.
- the field particularly targeted is that of pressure sensors usable at very low temperatures, typically temperatures below that of boiling nitrogen, and can go down to a few Kelvin.
- networks of compensation connected to the inputs and / or outputs of the bridge are usually designed to carry out a compensation of linear type, the thermal drift of the bridges of gauges being substantially linear in the usual temperature ranges.
- JP-A-62 121 302 discloses a four-gauge circuit mounted in the branches of a bridge of Wheatstone. In a bridge top, two resistive elements arranged in parallel are provided to compensate for bridge drift as a function of temperature.
- the problem that the present invention aims to solve is to compensate the non-linearity of the thermal drift and, consequently, to "linearize” it at very low temperatures, especially at temperatures below nitrogen boiling, that is to say below -196 ° C.
- the resistance on which the compensation circuit is connected in parallel to a much lower value than that of the strain gauge, so that not penalize the extent of the operating range and the sensitivity of the bridge.
- much lower value here means a value less than 1/20, even 1/100 or less of the resistance of an extensometer.
- the compensation circuit is connected in parallel to a resistor formed by a Connection strand connecting the strain gauge to a top of the bridge.
- non-linearity compensation circuit can thus be placed closer to the bridge, so be exposed exactly to the same conditions of temperature as the bridge.
- the resistive element of the compensation must have a resistance such that it influences that of the resistance on which it is connected in parallel, and this more and more when the temperature decreases.
- the relationship between the resistance of the resistive element and that of the resistor on which it is connected in parallel not more than 100, when the temperature falls below -196 ° C, and then decreases when the temperature decreases.
- a resistive element is by example consisting of a platinum probe.
- FIG. 2 illustrates the diagram of a pressure sensor comprising four strain gauges J1, J2, J3, J4 inserted respectively into the four branches of a Wheatstone bridge 10.
- the gauges J1 to J4 are each connected to two adjacent vertices of bridge by connecting strands c .
- the gauges J1 to J4 and the connection strands c are formed by metal deposits on a substrate, for example silicon, forming part of the sensitive element of the sensor.
- a substrate for example silicon
- two gauges mounted in two opposite branches of the bridge are arranged on the substrate so as to be biased in extension, when the substrate is subjected to a pressure to be measured, while the two other gauges are arranged so as to be solicited in compression.
- the gauges J1 to J4 are for example formed by nickel-chromium deposits, which are as identical as possible, while the connecting strands c are formed, for example, by gold deposits, which are also as identical as possible.
- the deposits are made in a thin layer, for example by projection under vacuum, closing the bridge being performed by the deposits made.
- a compensation network 12 is interposed between the vertices + a, -a, + m, -m on the one hand, and the terminals + A, -A, + M, -M, on the other hand.
- the compensation network 12 aims to achieve linear drift compensation pressure sensor as a function of temperature. It is a resistive network, of a type well known per se, for example as described in the document FR-A 2,613,833.
- a bridge drift non-linearity compensation circuit 20 is connected in parallel on a connection wire c connecting one of the bridge gauges, for example the gauge J2, to one of the two vertices of the end bridge. of the branch containing the gauge, for example the vertex + m.
- the compensation circuit 20 comprises a resistive element P whose resistance is variable depending on the temperature, especially in the very low temperature range, that is to say, typically the temperatures below the boiling point of nitrogen (-196 ° C).
- a setting resistance R can be connected in series with the resistive element P, in the circuit of compensation, in order to allow an adjustment of the compensation achieved.
- the mounting of the resistive element in parallel on a constituent part of the total resistance of a branch of the bridge makes it possible to influence in a non-linear manner the behavior of the bridge, thus to make a compensation of non-linearity of drift.
- the influence of the resistive element P must increase, so its resistance decreases so that the ratio between this resistance and that of a connection strand c become at most 100 when the temperature falls below -196 ° C and decreases when the temperature decreases below -196 ° C.
- a resistive element P having a positive temperature coefficient, for example a platinum probe, is then used.
- a pressure sensor as shown in FIG. 2 was made with strain gauges formed by nickel-chromium thin film deposition, each gauge having a resistance of 1000 ⁇ at room temperature (22 ° C).
- Connection strands c are thin film gold linear deposits each having a resistance of 0.6 ⁇ at 22 ° C.
- FIG. 1 shows the evolution of the voltage collected at the vertices + m, -m bridge in the absence of constraints on the sensor, and in the absence of the network of compensation 12 and the compensation circuit 20, the balance of the bridge (voltage of zero output) being made at 22 ° C.
- the zero drift of the bridge mainly due to gauges, becomes more and more pronounced as the temperature decreases. Up to about -140 ° C, the drift is substantially linear. To the most low temperatures, the non-linearity of the drift becomes more and more perceptible.
- a compensation circuit consisting of a platinum probe P of resistance equal to 100 ⁇ at 0 ° C in series with a setting resistance R is placed in parallel on the gold connecting wire connecting the gauge J2 to the top + m of the bridge.
- Table 1 shows the values of the resistances of a connection strand c and the probe P, the setting resistance R being zero as well as the equivalent resistance of the parallel circuit formed by P and c , at different temperatures.
- the ratio of the resistances of the probe P to the connecting strand c increases from about 47 to about 7.9 between -196 ° C and -246 ° C.
- the introduction of the compensation circuit 20 results in a zero offset of the bridge, which increases when the temperature decreases.
- Table 2 gives the value of the offset ⁇ Z, measured in output voltage of the bridge, the gauges are not under stress (with 800 ⁇ gauges, a 6.4 ⁇ offset of a gauge produces a voltage of 20 mV output when the bridge is powered at 10 V).
- the different offsets ⁇ Z shown in Table 2 correspond to different values of the compensation circuit and different temperatures.
- the rows of the table show that the offset can be attenuated by increasing the value of R or accentuated by decreasing the value of P (by placing for example two 100 ⁇ probes in parallel).
- the choice of the compensation circuit is therefore a function of the degree of non-linearity to be corrected.
- Figure 3 shows the evolution of the voltage collected between the peaks + m, -m of the bridge, under the same conditions as for FIG. stress on the sensor, bridge zero at 22 ° C and no compensation linear, but with different compensation circuits 20 including resistance R in series with two probes P in parallel, each probe P being a platinum probe with a resistance of 100 ⁇ at 0 ° C.
- the circuit of compensation is connected either on one and / or the other of two opposite branches of the bridge, either on one and / or the other of the other two opposite branches of the bridge.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Force In General (AREA)
- Measuring Fluid Pressure (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Description
La présente invention concerne un capteur de pression du type comportant des jauges extensométriques montées respectivement dans les branches d'un pont de Wheatstone.The present invention relates to a pressure sensor of the type with strain gauges mounted respectively in the branches of a Wheatstone bridge.
Le domaine plus particulièrement visé est celui des capteurs de pression utilisables à de très basses températures, typiquement des températures inférieures à celle d'ébullition de l'azote, et pouvant descendre jusqu'à quelques Kelvin. Arrière-plan de l'invention The field particularly targeted is that of pressure sensors usable at very low temperatures, typically temperatures below that of boiling nitrogen, and can go down to a few Kelvin. Background of the invention
Un problème bien connu des capteurs de pression à jauges extensométriques montées en pont de Wheatstone est celui de la dérive de zéro du pont en fonction de la température.A well known problem of gauge pressure sensors Wheatstone bridge-type extensometer is that of the zero drift of the bridge depending on the temperature.
Pour résoudre ce problème, il est généralement fait appel à des réseaux de compensation branchés aux entrées et/ou sorties du pont. Ces réseaux, qui utilisent au moins un élément sensible à la température, sont habituellement conçus pour réaliser une compensation de type linéaire, la dérive thermique des ponts de jauges étant sensiblement linéaire dans les plages de températures usuelles.To solve this problem, networks of compensation connected to the inputs and / or outputs of the bridge. These networks, which use at least one temperature sensitive element, are usually designed to carry out a compensation of linear type, the thermal drift of the bridges of gauges being substantially linear in the usual temperature ranges.
JP-A-62 121 302 décrit un circuit à quatre jauges montées dans les branches d'un pont de Wheatstone. Dans un sommet du pont, deux éléments résistifs disposés en parallèle sont prévus pour compenser la dérive du pont en fonction de la température.JP-A-62 121 302 discloses a four-gauge circuit mounted in the branches of a bridge of Wheatstone. In a bridge top, two resistive elements arranged in parallel are provided to compensate for bridge drift as a function of temperature.
Une difficulté supplémentaire surgit lorsque les capteurs de pression sont utilisés aux très basses températures. En effet, la dérive thermique des ponts de jauges devient non linéaire, et cette non-linéarité s'accroít lorsque la température décroít. Cela est illustré par la figure 1 qui montre l'évolution en fonction de la température de la tension de sortie d'un pont de jauges formées par des dépôts de nickel-chrome en couche mince sur un substrat en silicium, le pont étant équilibré (tension de sortie nulle) pour une température de 22°C.An additional difficulty arises when the pressure sensors are used at very low temperatures. Indeed, the thermal drift of bridges gauges becomes non-linear, and this non-linearity increases when the temperature decreases. This is illustrated in Figure 1 which shows the evolution according to the temperature of the output voltage of a bridge of gauges formed by deposits of nickel-chromium thin film on a silicon substrate, the bridge being balanced (zero output voltage) for a temperature of 22 ° C.
Les réseaux de compensation usuels deviennent inefficaces, et ce d'autant que les thermistances utilisées habituellement présentent souvent une résistance qui devient extrêmement élevée, quasi infinie, lorsque la température devient inférieure à -40°C ou -50°C.The usual compensation networks become ineffective, and all that thermistors used usually often have a resistance which becomes extremely high, almost infinite, when the temperature becomes below -40 ° C or -50 ° C.
Le problème que vise à résoudre la présente invention est de compenser la non-linéarité de la dérive thermique et, par conséquent, de "linéariser" celle-ci aux très basses températures, en particulier aux températures inférieures au point d'ébullition de l'azote, c'est-à-dire inférieures à -196°C environ.The problem that the present invention aims to solve is to compensate the non-linearity of the thermal drift and, consequently, to "linearize" it at very low temperatures, especially at temperatures below nitrogen boiling, that is to say below -196 ° C.
Ce problème est résolu grâce à un capteur de pression tel que défini dans la revendication 1. This problem is solved thanks to a pressure sensor as defined in claim 1.
La résistance sur laquelle le circuit de compensation est branché en parallèle a une valeur très inférieure à celle de la jauge extensométrique, afin de ne pas pénaliser l'étendue de la plage de fonctionnement et la sensibilité du pont. Par valeur très inférieure, on entend ici une valeur inférieure à 1/20, voire 1/100 ou moins de la résistance d'une jauge extensométrique.The resistance on which the compensation circuit is connected in parallel to a much lower value than that of the strain gauge, so that not penalize the extent of the operating range and the sensitivity of the bridge. By much lower value, here means a value less than 1/20, even 1/100 or less of the resistance of an extensometer.
Selon une caractéristique du capteur de pression conforme à l'invention, le circuit de compensation est branché en parallèle sur une résistance formée par un brin de connexion reliant la jauge extensométrique à un sommet du pont.According to a characteristic of the pressure sensor according to the invention, the compensation circuit is connected in parallel to a resistor formed by a Connection strand connecting the strain gauge to a top of the bridge.
Ainsi, aucune modification du pont n'est nécessaire pour insérer le circuit de compensation. On évite ainsi les instabilités qui pourraient être engendrées si une ouverture du pont était nécessaire à cet effet.Thus, no modification of the bridge is necessary to insert the circuit compensation. This avoids the instabilities that could be generated if an opening of the bridge was necessary for this purpose.
En outre, le circuit de compensation de non-linéarité peut ainsi être placé au plus près du pont, donc être exposé exactement aux mêmes conditions de température que le pont.In addition, the non-linearity compensation circuit can thus be placed closer to the bridge, so be exposed exactly to the same conditions of temperature as the bridge.
Pour compenser la non-linéarité dans le domaine des très basses températures, c'est-à-dire en deçà de -196°C, l'élément résistif du circuit de compensation doit avoir une résistance telle qu'elle influence celle de la résistance sur lequel il est branché en parallèle, et ce de façon croissante lorsque la température diminue. A cet effet, il est préférable que le rapport entre la résistance de l'élément résistif et celle de la résistance sur laquelle il est branché en parallèle soit au plus égal à 100, lorsque la température devient inférieure à -196°C, et diminue ensuite lorsque la température décroít. Un tel élément résistif est par exemple constitué par une sonde en platine.To compensate for the non-linearity in the field of very low temperatures, that is to say below -196 ° C, the resistive element of the compensation must have a resistance such that it influences that of the resistance on which it is connected in parallel, and this more and more when the temperature decreases. For this purpose, it is preferable that the relationship between the resistance of the resistive element and that of the resistor on which it is connected in parallel not more than 100, when the temperature falls below -196 ° C, and then decreases when the temperature decreases. Such a resistive element is by example consisting of a platinum probe.
Dans les dessins annexés,
- la figure 1 illustre la variation, en fonction de la température, de la dérive de zéro d'un capteur de pression formé par un pont de jauges extensométriques, en l'absence de compensation de dérive,
- la figure 2 est un schéma électrique d'un mode de réalisation d'un capteur de pression conforme à l'invention, et
- la figure 3 illustre la variation, en fonction de la température, de la dérive de zéro du capteur de pression de la figure 1, muni d'un circuit de compensation de non-linéarité de dérive thermique, conformément à l'invention.
- FIG. 1 illustrates the variation, as a function of temperature, of the zero drift of a pressure sensor formed by a bridge of strain gauges, in the absence of drift compensation,
- FIG. 2 is a circuit diagram of one embodiment of a pressure sensor according to the invention, and
- FIG. 3 illustrates the variation, as a function of temperature, of the zero drift of the pressure sensor of FIG. 1, provided with a thermal drift non-linearity compensation circuit, according to the invention.
La figure 2 illustre le schéma d'un capteur de pression comprenant quatre
jauges extensométriques J1, J2, J3, J4 insérées respectivement dans les quatre
branches d'un pont de Wheatstone 10. Les jauges J1 à J4 sont reliées chacune à
deux sommets adjacents du pont par des brins de connexion c.FIG. 2 illustrates the diagram of a pressure sensor comprising four strain gauges J1, J2, J3, J4 inserted respectively into the four branches of a Wheatstone
Les jauges J1 à J4 et les brins de connexion c sont formés par des dépôts métalliques sur un substrat, par exemple en silicium, faisant partie de l'élément sensible du capteur. De façon bien connue, deux jauges montées dans deux branches opposées du pont sont disposées sur le substrat de manière à être sollicitées en extension, lorsque le substrat est soumis à une pression à mesurer, tandis que les deux autres jauges sont disposées de manière à être sollicitées en compression.The gauges J1 to J4 and the connection strands c are formed by metal deposits on a substrate, for example silicon, forming part of the sensitive element of the sensor. In a well known manner, two gauges mounted in two opposite branches of the bridge are arranged on the substrate so as to be biased in extension, when the substrate is subjected to a pressure to be measured, while the two other gauges are arranged so as to be solicited in compression.
Les jauges J1 à J4 sont par exemple formées par des dépôts en nickel-chrome, aussi identiques que possible, tandis que les brins de connexion c sont par exemple formés par des dépôts en or, également aussi identiques que possible.The gauges J1 to J4 are for example formed by nickel-chromium deposits, which are as identical as possible, while the connecting strands c are formed, for example, by gold deposits, which are also as identical as possible.
Les dépôts sont réalisés en couche mince, par exemple par projection sous vide, la fermeture du pont étant réalisée par les dépôts réalisés.The deposits are made in a thin layer, for example by projection under vacuum, closing the bridge being performed by the deposits made.
Deux sommets opposés +a et -a du pont sont reliés à des bornes
d'alimentation +A et -A tandis que les deux autres sommets +m et -m sont reliés à
des bornes de mesure +M et -M. Un réseau de compensation 12 est interposé entre
les sommets +a, -a, +m, -m d'une part, et les bornes +A, -A, +M, -M, d'autre part.
Le réseau de compensation 12 vise à réaliser une compensation de dérive linéaire
du capteur de pression en fonction de la température. Il s'agit d'un réseau résistif,
de type bien connu en soi, par exemple tel que décrit dans le document
FR-A 2 613 833.Two opposite peaks + a and -a of the bridge are connected to terminals
supply + A and -A while the other two vertices + m and -m are connected to
measuring terminals + M and -M. A
Un circuit 20 de compensation de non-linéarité de dérive de zéro du pont
est branché en parallèle sur un brin de connexion c reliant une des jauges du pont,
par exemple la jauge J2, à l'un des deux sommets du pont situé aux extrémités de
la branche contenant la jauge, par exemple le sommet +m.A bridge drift
Le circuit de compensation 20 comprend un élément résistif P dont la
résistance est variable en fonction de la température, en particulier dans le
domaine des très basses températures, c'est-à-dire, typiquement, les températures
inférieures au point d'ébullition de l'azote (-196°C). Une résistance de réglage R
peut être branchée en série avec l'élément résistif P, dans le circuit de
compensation, afin de permettre un ajustage de la compensation réalisée.The
Le montage de l'élément résistif en parallèle sur une partie constitutive de la résistance totale d'une branche du pont permet d'influencer de façon non linéaire le comportement du pont, donc de réaliser une compensation de non-linéarité de dérive. Lorsque cette non-linéarité s'accroít au fur et à mesure que la température décroít, l'influence de l'élément résistif P doit croítre, donc sa résistance décroítre de sorte que le rapport entre cette résistance et celle d'un brin de connexion c devienne au plus égal à 100 lorsque la température devient inférieure à -196°C et diminue lorsque la température décroít en deçà de -196°C. On utilise alors un élément résistif P ayant un coefficient de température positif, par exemple une sonde en platine.The mounting of the resistive element in parallel on a constituent part of the total resistance of a branch of the bridge makes it possible to influence in a non-linear manner the behavior of the bridge, thus to make a compensation of non-linearity of drift. When this non-linearity increases as the temperature decreases, the influence of the resistive element P must increase, so its resistance decreases so that the ratio between this resistance and that of a connection strand c become at most 100 when the temperature falls below -196 ° C and decreases when the temperature decreases below -196 ° C. A resistive element P having a positive temperature coefficient, for example a platinum probe, is then used.
Un capteur de pression tel qu'illustré par la figure 2 a été réalisé avec des jauges extensométriques formées par un dépôt en couche mince de nickel-chrome, chaque jauge ayant une résistance de 1 000 Ω à température ambiante (22°C). Les brins de connexion c sont des dépôts linéaires d'or en couche mince ayant chacune une résistance de 0,6 Ω à 22°C.A pressure sensor as shown in FIG. 2 was made with strain gauges formed by nickel-chromium thin film deposition, each gauge having a resistance of 1000 Ω at room temperature (22 ° C). Connection strands c are thin film gold linear deposits each having a resistance of 0.6 Ω at 22 ° C.
La figure 1 montre l'évolution de la tension recueillie aux sommets +m,
-m du pont en l'absence de contraintes sur le capteur, et en l'absence du réseau de
compensation 12 et du circuit de compensation 20, l'équilibre du pont (tension de
sortie nulle) étant réalisé à 22°C.FIG. 1 shows the evolution of the voltage collected at the vertices + m,
-m bridge in the absence of constraints on the sensor, and in the absence of the network of
On constate que la dérive de zéro du pont, due essentiellement aux jauges, devient de plus en plus prononcée au fur et à mesure que la température décroít. Jusqu'à environ -140°C, la dérive est sensiblement linéaire. Vers les plus basses températures, la non-linéarité de la dérive devient de plus en plus perceptible.It can be seen that the zero drift of the bridge, mainly due to gauges, becomes more and more pronounced as the temperature decreases. Up to about -140 ° C, the drift is substantially linear. To the most low temperatures, the non-linearity of the drift becomes more and more perceptible.
Un circuit de compensation constitué d'une sonde en platine P de résistance égale à 100 Ω à 0°C en série avec une résistance de réglage R est placé en parallèle sur le brin de connexion en or reliant la jauge J2 au sommet +m du pont.A compensation circuit consisting of a platinum probe P of resistance equal to 100 Ω at 0 ° C in series with a setting resistance R is placed in parallel on the gold connecting wire connecting the gauge J2 to the top + m of the bridge.
Le tableau 1 ci-dessous montre les valeurs des résistances d'un brin de
connexion c et de la sonde P, la résistance de réglage R étant nulle ainsi que de la
résistance équivalente du circuit parallèle formé par P et c, à différentes
températures. Le rapport entre les résistances de la sonde P et du brin de
connexion c passe de 47 environ à 7,9 environ entre -196°C et -246°C.
L'introduction du circuit de compensation 20 se traduit par un décalage
du zéro du pont, décalage qui augmente lorsque la température décroít. Le tableau
2 ci-dessous donne la valeur du décalage ΔZ, mesuré en tension de sortie du pont,
les jauges n'étant pas sous contrainte (avec des jauges de 800 Ω, un décalage de
6.4 Ω d'une jauge produit une tension de sortie de 20 mV lorsque le pont est
alimenté sous 10 V). Les différents décalages ΔZ indiqués dans le tableau 2
correspondent à différentes valeurs du circuit de compensation et différentes
températures. Les lignes du tableau montrent que le décalage peut être atténué en
augmentant la valeur de R ou accentué en diminuant la valeur de P (en plaçant par
exemple deux sondes de 100 Ω en parallèle). Le choix du circuit de compensation
est donc fonction du degré de non-linéarité à corriger.
La figure 3 montre l'évolution de la tension recueillie entre les sommets
+m, -m du pont, dans les mêmes conditions que pour la figure 1, à savoir absence
de contraintes sur le capteur, zéro du pont réalisé à 22°C et pas de compensation
linéaire, mais avec différents circuits de compensation 20 comprenant une
résistance R en série avec deux sondes P en parallèle, chaque sonde P étant une
sonde en platine de résistance égale à 100 Ω à 0°C. Figure 3 shows the evolution of the voltage collected between the peaks
+ m, -m of the bridge, under the same conditions as for FIG.
stress on the sensor, bridge zero at 22 ° C and no compensation
linear, but with
On constate que, par rapport à la courbe I donnant l'évolution de la dérive
de zéro en l'absence de circuit de compensation 20, la correction de non-linéarité
est d'autant plus accentuée que la résistance de R est plus petite. Dans cet
exemple, pour R = 4 Ω et avec deux sondes P en parallèle, la dérive de zéro du
pont est linéarisée jusqu'à de très faibles températures (environ -250°C). Par
l'action du réseau de compensation linéaire 12, il est alors possible de compenser
totalement la dérive thermique de zéro du pont depuis la température ambiante
jusqu'aux très basses températures (quelques Kelvin).It can be seen that, with respect to the curve I giving the evolution of the drift
of zero in the absence of
Dans ce qui précède, il est envisagé de connecter un circuit de compensation de non-linéarité de dérive sur un des brins de connexion reliant une jauge extensométrique d'une des branches du pont à un sommet de celui-ci. Il est envisageable, pour aboutir au même effet, de brancher un circuit de compensation de non-linéarité de dérive sur l'un et/ou l'autre des brins de connexion de cette branche du pont et/ou sur l'un et/ou l'autre des brins de connexion de la branche opposée.In what precedes, it is envisaged to connect a circuit of drift non-linearity compensation on one of the connection strands connecting a strain gauge of one of the branches of the bridge at an apex of it. It is possible, to achieve the same effect, to connect a compensation circuit of non-linearity of drift on one and / or the other of the connection strands of this branch of the bridge and / or on one and / or the other branch of the branch opposite.
Dans le cas de la figure 1, la non-linéarité évolue dans le même sens que la composante de dérive linéaire et aggrave celle-ci, mais elle pourrait dans d'autres cas évoluer dans l'autre sens. Selon le sens de cette évolution, le circuit de compensation est connecté soit sur l'une et/ou l'autre de deux branches opposées du pont, soit sur l'une et/ou l'autre des deux autres branches opposées du pont.In the case of Figure 1, the non-linearity evolves in the same direction as the linear drift component and worsens it, but it could in other cases evolve in the other direction. According to the meaning of this evolution, the circuit of compensation is connected either on one and / or the other of two opposite branches of the bridge, either on one and / or the other of the other two opposite branches of the bridge.
Claims (5)
- A pressure sensor likely to be used in a very low temperature range, including temperatures below -196°C, and comprising strain gauges (J1 to J4) mounted in respective arms of a Wheatstone bridge (10) and connection leads (c) connecting each strain gauge to two adjacent corners of the bridge and having resistances that are much less than those of the strain gauges, the strain gauges (J1 to J4) and the connection leads (c) being constituted by deposits of metal on a substrate,
the sensor being characterised in that a circuit is further provided for compensating non-linearity in zero drift of the bridge in said very low temperature range, with the compensation circuit comprising a resistive element (P) which is connected in parallel with a connection lead (c) between a strain gauge and a corner of the bridge and whose resistance varies as a function of temperature so as to influence the resistances of the connection lead with which it is connected in parallel, in said very low temperature range, in a manner that is sensitive to temperature and that increases with decreasing temperature. - A sensor according to claim 1, characterised in that the connection leads (c) are made of gold.
- A sensor according to any one of claims 1 and 2, characterised in that the ratio of the resistance of said resistive element (P) to the resistance of the resistor (c) with which it is connected in parallel is no greater than 100 when the temperature drops below -196°C, and thereafter decreases with decreasing temperature.
- A sensor according to any one of claims 1 to 3, characterised in that said resistive element (P) is constituted by at least one platinum probe.
- A sensor according to any one of claims 1 to 4, characterised in that said compensation circuit (20) includes an adjustable resistor (R) connected in series with said resistive element (P).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9803437 | 1998-03-20 | ||
| FR9803437A FR2776384B1 (en) | 1998-03-20 | 1998-03-20 | PRESSURE SENSOR WITH COMPENSATION FOR THE NON-LINEARITY OF THE ZERO DRIFT AT VERY LOW TEMPERATURES |
| PCT/FR1999/000637 WO1999049288A1 (en) | 1998-03-20 | 1999-03-19 | Pressure sensor with compensation for null shift non-linearity at very low temperatures |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0990128A1 EP0990128A1 (en) | 2000-04-05 |
| EP0990128B1 true EP0990128B1 (en) | 2005-08-24 |
Family
ID=9524275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99910415A Expired - Lifetime EP0990128B1 (en) | 1998-03-20 | 1999-03-19 | Pressure sensor with compensation for null shift non-linearity at very low temperatures |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US6314815B1 (en) |
| EP (1) | EP0990128B1 (en) |
| JP (1) | JP4131990B2 (en) |
| CN (1) | CN1144032C (en) |
| DE (1) | DE69926847T2 (en) |
| ES (1) | ES2246565T3 (en) |
| FR (1) | FR2776384B1 (en) |
| WO (1) | WO1999049288A1 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6701790B2 (en) * | 2002-06-13 | 2004-03-09 | Mykrolis Corporation | Temperature regulator for use with a pressure sensing device |
| CN101275876B (en) * | 2007-03-27 | 2011-05-11 | 豪威国际控股有限公司 | Design method of bridge arm balance compensating resistance of pressure sensor signal conditioning integrate circuit |
| JP5066010B2 (en) * | 2008-06-09 | 2012-11-07 | 株式会社タニタ | Multi-point scale and manufacturing method thereof |
| US7938016B2 (en) * | 2009-03-20 | 2011-05-10 | Freescale Semiconductor, Inc. | Multiple layer strain gauge |
| CN101887081B (en) * | 2010-06-29 | 2012-09-05 | 三一重工股份有限公司 | Bridge zero adjustment circuit |
| CN102252700B (en) * | 2011-04-29 | 2012-08-22 | 中北大学 | Micro-cantilever beam piezoresistive bridge type sensor detecting instrument |
| JP6490039B2 (en) * | 2016-10-21 | 2019-03-27 | ミネベアミツミ株式会社 | Strain gauge |
| CN106595832B (en) * | 2016-12-07 | 2023-05-02 | 锐马（福建）电气制造有限公司 | Zero drift compensation workbench of weighing sensor |
| CN106802170B (en) * | 2016-12-30 | 2019-07-19 | 北京七星华创流量计有限公司 | Flow sensor, mass flow conveying measure and control device and its temperature drift suppressing method |
| CN110823446B (en) * | 2019-10-18 | 2022-01-07 | 成都凯天电子股份有限公司 | Secondary temperature compensation zero debugging method for silicon piezoresistive pressure sensor |
| CN113639903A (en) * | 2021-07-13 | 2021-11-12 | 西安理工大学 | Stress detection method in FDM printing process |
| CN117030098B (en) * | 2023-09-28 | 2024-02-27 | 无锡菲欧科技有限公司 | Double-pressure output sensor with temperature compensation |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3645136A (en) * | 1970-04-15 | 1972-02-29 | Charles W Calhoun | Fluid pressure measuring device |
| JPS55163880A (en) * | 1979-06-07 | 1980-12-20 | Hitachi Ltd | Semiconductor strain gauge bridge circuit |
| US4333349A (en) * | 1980-10-06 | 1982-06-08 | Kulite Semiconductor Products, Inc. | Binary balancing apparatus for semiconductor transducer structures |
| FR2497346A1 (en) * | 1980-12-31 | 1982-07-02 | Gi Teploene | Semiconductor extension transducer - has monocrystalline substrate carrying surface resistances connected in bridge circuit |
| US4414853A (en) * | 1981-08-10 | 1983-11-15 | The Foxboro Company | Pressure transmitter employing non-linear temperature compensation |
| JPS62121302A (en) * | 1985-11-21 | 1987-06-02 | Kyowa Electronic Instr Corp Ltd | Temperature compensating circuit in strain gauge type converter, and its temperature compensating method |
| JPH0797010B2 (en) * | 1986-03-26 | 1995-10-18 | 株式会社日立製作所 | Semiconductor strain gage bridge circuit |
| ES2132628T3 (en) * | 1994-12-02 | 1999-08-16 | Getinge Ab | A TEMPERATURE COMPENSATION METHOD IN PRESSURE SENSORS. |
-
1998
- 1998-03-20 FR FR9803437A patent/FR2776384B1/en not_active Expired - Fee Related
-
1999
- 1999-03-19 US US09/424,161 patent/US6314815B1/en not_active Expired - Lifetime
- 1999-03-19 ES ES99910415T patent/ES2246565T3/en not_active Expired - Lifetime
- 1999-03-19 DE DE69926847T patent/DE69926847T2/en not_active Expired - Lifetime
- 1999-03-19 WO PCT/FR1999/000637 patent/WO1999049288A1/en active IP Right Grant
- 1999-03-19 EP EP99910415A patent/EP0990128B1/en not_active Expired - Lifetime
- 1999-03-19 JP JP54786099A patent/JP4131990B2/en not_active Expired - Lifetime
- 1999-03-19 CN CNB998003352A patent/CN1144032C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999049288A1 (en) | 1999-09-30 |
| ES2246565T3 (en) | 2006-02-16 |
| CN1262738A (en) | 2000-08-09 |
| JP4131990B2 (en) | 2008-08-13 |
| FR2776384B1 (en) | 2000-06-23 |
| CN1144032C (en) | 2004-03-31 |
| JP2001527652A (en) | 2001-12-25 |
| FR2776384A1 (en) | 1999-09-24 |
| DE69926847T2 (en) | 2006-06-29 |
| DE69926847D1 (en) | 2005-09-29 |
| EP0990128A1 (en) | 2000-04-05 |
| US6314815B1 (en) | 2001-11-13 |
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